Combustion apparatus

ABSTRACT

A combustion apparatus for incinerating non-homogeneous pumpable liquid wastes. A watery waste fraction and an oily waste fraction are introduced into a reaction chamber as separate aerosol streams. Combustion air and auxiliary gaseous fuel are used as propellants to produce the aerosol streams. The liquid waste injector includes a central atomizing nozzle for the watery waste liquid fraction and a surrounding annular conduit for auxiliary fuel and combustion air. Around the outside of this first annular conduit is a second annular conduit having a concentrically mounted annular nozzle at the end thereof for producing an aerosol from the oily waste liquid fraction. A high velocity gas stream contacts the oily waste as it is discharged from the nozzle and causes it to flow in a thin sheet over a surface portion of the annular nozzle to an edge thereof where it encounters a second high velocity gas stream directed perpendicularly with respect to the surface. The injector is coaxially mounted on the end of a cylindrical reaction chamber. An annular step is provided at the entrance end of the reaction chamber a short distance downstream from the injector nozzle to shield the chamber surface by preventing wall attachment of the burner flames. A helically swirling annular column of combustion air is supplied around the injector.

United States Patent [1 1 Hemsath et al.

[ Oct. 30, 1973 COMBUSTION APPARATUS [75] Inventors: Klaus H. Hemsath,Sylvania; Dale E.

Wright, Perrysburg, both of Ohio [73] Assignee: Midland-RossCorporation,

Cleveland, 0hio [22] Filed: Oct. 19, 1972 [21] Appl. No.: 299,030

Related U.S. Application Data [62] Division of Ser. No. 193,865, Oct.29, 1971, Pat. No.

Primary Examiner-Edward G. Favors Att0meyPeter Vrahotes [57] ABSTRACT Acombustion apparatus for incinerating nonhomogeneous pumpable liquidwastes. A watery waste fraction and an oily waste fraction areintroduced into a reaction chamber as separate aerosol streams.Combustion air and auxiliary gaseous fuel are used as propellants toproduce the aerosol streams. The liquid waste injector includes acentral atomizing nozzlefor the watery waste liquid fraction and asurrounding annular conduit for auxiliary fuel and combustion air.Around the outside of this first annular conduit is a second annularconduit having a concentrically mounted annular nozzle at the endthereof for producing an aerosol from the oily waste liquid fraction. Ahigh velocity gas stream contacts the oily waste as it is dischargedfrom the nozzle and causes it to flow in a thin sheet over a surfaceportion of the annular nozzle to an edge thereof where it encounters asecond high velocity gas stream directed perpendicularly with respect tothe surface. The injector is coaxially mounted on the end of acylindrical reaction chamber. An annular step is provided at theentrance end of the reaction chamber a short distance downstream fromthe injector nozzle to shield the chamber surface by preventing wallattachment of the burner flames. A helically swirling annular column ofcombustion air is supplied around the injector.

4 Claims, 3 Drawing Figures V COMBUSTION APPARATUS This is a division,of U.S. Pat. application Ser. No.

193,865, filed Oct. 29, 1971 and now U.S. Pat. No.

BACKGROUND OF THE INVENTION Many devices have been developed fordisposing of liquid wastes by combustion processes. Some of theseevaporate or distill the liquid wastes until only sludges or solidmaterials remain and then incinerate the concentrates. When attemptswere made to incinerate liquid wastes directly, numerous problems wereencountered. One of the primary problems encountered was the difficultyof maintaining a stable flame. Normally the liquid waste wasnon-homogeneous in character and had a tendency to separate intofractions having widely varying fuel values before reaching the burnernozzle. Emulsifying agents and mixing devices were employed to produceuniformity, but were not completely satisfactory. Another problem wasthat most unseparated wastes containing high amounts of water wereincapable of supporting combustion. As a result, additional fuel wasrequired even though the fuel value of the waste'mixture was sufficientfor its incineration. The extra fuel was otherwise wasted because itsfinal effect was to drive the flue gas temperature above the requiredincineration temperature.

Variances in the physical properties, such as viscosity and size of thesuspended particles of the wasteliquid components also made if difficulttoatomize the liquid waste. An atomizer capable of atomizing the highestviscosity component of the liquid waste would be inefficient for thelower viscosity components. Conventional atomizers require relativelyminute outlet orifices and are readily clogged by the relatively largesuspended particles normally found in liquid wastes. These factorslimited the prior art devices to the disposal of refined liquid wastesand also limited the recovery of the heating value from combustiblewastes.

SUMMARY OF THE INVENTION Generally speaking, this invention relates to acornbustion apparatus in which two liquid fuels having different fuelvalues are injected separately intola combustion chamber. Moreparticularly, it pertains to a liquid waste incinerator having means forseparating the liquid waste into two fractions and injecting thesefractions separately into a mixing and incineration chamber where theyare rapidly combined with the necessary quantities of gaseous fuel andcombustion air. Preferably the incineration chamber is a refractorylined cylinder with a burner chamber containing a'waste liquid injectionmeans at its entrance end. The injection means may include aconventional type atomizer for atomizing the lower viscosity or wateryfraction of the liquid waste. The atomizer is aligned with the axis ofthe incineration chamber. A first annular conduit for supplying gaseousfuel and air surrounds the aforesaid atomizer. A second annular conduitsurrounds the first annular conduit and has an annular atomizing nozzleat its distal end. The higher viscosity or oily fraction of the liquidwaste is supplied to an annular outlet in aninternal head section of thenozzle. The annular nozzle and its internal head section are designed sothat a pressurized gas stream flowing around one side of the headcontacts the liquid waste and causes it to flow in a thin film across asurface portion of the head. As the thin film reaches the edge of thissurface it is contacted by another gas stream flowing around the headfrom the other side. At the annular line of contact the second gasstream is flowing in a direction substantially perpendicular to the flowdirection of the waste liquid film, and in this manner readily breaksthe thin film of liquid into fine droplets as it leaves the edge of thesurface. Means may be provided to vary the relative volumetric flow rateof the two ga s streams. A wind box located at the base of the injectionmeans supplies a helically swirling column of combustion air around theinjected fluid streams. The aerosol produced by the annular atomizer israpidly mixed with this surrounding stream of combustion air. An abruptoffset or annular step extending radially inward from the entrance endof the incineration chamber prevents wall attachment of the hot gasesemanating from the burner. With the above arrangement, the combustion ofthe aerosol stream from the annular atomizer may be substantiallycompleted before it becomes mixed with the centrally flowing aerosolfrom the conventional atomizer. This is particularly important when thelower viscosity liquid waste fraction is a watery waste havingrelatively low fuel value such that a burner flame would be quenched ifthe atomized watery waste were injected directly into the base of theflame.

Although the primary purpose of the teachings herein is the incinerationof liquid waste, it is to be under'stood that the teachings are alsoapplicable to the combustion of liquid fuels other than fuels containingwaste material. For example, Bunker fuel could be substituted for theoily waste fraction and a light grade of fuel oil substituted for thewatery waste fraction.

It is a general object of this invention to produce a simple andefficient liquid waste incinerator which is capable of economicallyincinerating a wide variety of fluid wastes including waste gaseswithout altering its structure, but by merely changing the operatingprocedures. 1

It is still another object of this invention to produce an incineratorfor non-homogeneous liquid waste with improved flame stability.

It is another object of this invention to produce an incinerator fornonhomogeneo'us liquid waste which uses the heating value of the wastemore effectively by dividing the liquid waste into at least twofractions and injecting them separately by a burner means into areaction chamber.

It is a more specific object of this invention to produce such anincinerator having an annular atomizer which is capable of passingrelatively large solid particles without clogging.

These objects and other objects and advantages, as well as the manner ofattaining them, will be apparent from the following descriptionmade'with reference t the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view ofthe incinerator and separating tank with parts broken away.

FIG. 2 is an enlarged vertical sectional view of the liquid wasteinjector.

FIG. 3 is a graph comparing the temperature distribution between theincineration system of this invention and a similar incineration systemin which the waste liquid fractions are admitted together as a mixture.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to the drawings, FIG. 1shows an incinera tor for nonhomogeneous pumpable liquid wastes. It hasa vertically disposed cylindrical incineration chamber 12 with arefractory lining 14. At the bottom or entrance end of the chamber 12,an injector 16 is provided to produce separate coaxial aerosol streamsfrom two waste liquid fractions. Alongside the chamber is a liquid wasteseparator 18, such as a settling tank, for separating the waste liquidinto an oily or high viscosity fraction 20 and a watery or low viscosityfraction 22. The oily waste fraction containing a higher amount ofcombustible material is fed from the top of the separator 18 to theinjector 16 through a supply line 24. The watery waste fractioncontaining a lower amount of combustiblematerial is conveyed to theinjector from the bottom of the separator through supply line 26.Variable speed pumps 28 and 30 and valves 32 and 34 may be provided toseparately control the pressures and flow rates of the fluids in thelines 24 and 26. A windbox 36 withacentrifugal blower and spin vanes ismounted around the injector to supply a helically swirling column ofcombustion air around the aerosol streams emanating from the injector.Waste gases or fumes having a sufficiently high oxygen content may besubstituted for the combustion air.

The injector 16 is concentrically mounted on the entrance end of theincinerator chamber 12 with an annular space between the outside of theinjector and the inside wall of the chamber entrance. It comprises atubular casing 38 having an enlarged base portion at one end and anozzle portion of reduced size at the other end. A first annular conduitis formed between the inside wall of the casing and the outside wall ofa first tubular member 40 concentrically mounted inside casing. Insidethe nozzle end of this conduit is an annular head 41 with an annularoutlet orifice in its top side. The head is designed to providepassageways 42 and 44 for a mixture of gaseous fuel and air to flow inan axial direction on both sides of the head between it and the walls ofthe casing and first tubular member. A flat annular disk 46 spaced abovethe top side of the head extends radially from the edge of the firsttubular member beyond the outlet orifice in the head to the outer edgeof the head. The annular surface portion 48 extending from the outletorifice to the outer edge of the head preferably is a flat surfaceparallel to the adjacent The oily of the disk 46. However, it may beslightly inclined or arcuate, provided the angle between it and theaxially disposed passageway 44 is abrupt, i.e., preferably within 10 orso of 90. With this arrangement a mixture of gaseous fuel and air issupplied under pressure to the annular conduit through separate inputpipes 52 and 53 respectively. It flows at a high velocity throughpassageway 42 along the periphery of tubular member 40, then radiallyoutward between the top side of the head and the bottom side of theannular disk. Theily fraction of the liquid waste, which is suppliedunder pressure through branch lines 54 of supply line 24 to the annularoutlet orifice, is driven radially outward in a thin film over surfaceportion 48 to the edge of the head 41 where it is struck by the gaseousstream flowing in a generally perpendicular direction through passageway44. Thus the thin film is broken into fine droplets which are readilycombined with the two turbulent streams of gaseous mixture between whichit is sandwiched as it leaves the annular atomizing nozzle throughannular gap 55. Preferably a means is provided for adjusting the conicalangle of the aerosol stream flowing from the annular nozzle. Variousmeans may be used to accomplish this purpose. For example, one

means comprises sleeve spacers 56 disposed between the head 41 and cap46 of the annular nozzle. Bolts 57 disposed in a circle extend in axialdirections through the components and draw them tightly together. Bychanging the length of the spacers 56 the width of the gap 55 may bevaried. This produces a change of momentum of the gaseous stream flowingthrough passageway 42 and gap 55 with a consequent change in therelative deflection between it and the angularly opposed gaseous streamflowing out of passageway 44.

A watery waste atomizer head 58 of a conventional type is located at theend of supply line 26 which extends along the axis of the injectorinside tubular member 40 forming a second annular conduit therewith. Thetip of the atomizing head 58 is located within a distance equivalent toone-half the inside diameter of tubular member 40 from the end oftubular member 40 and has a spray angle of between l5-30. Air which maybe combined with gaseous fuel is supplied under a pressure of more thanabout 3 pounds per square inch gauge to the second annular conduitthrough input pipe 60 to produce a high momentum annular gas streambetween atomizing head 58 and the surrounding annular atomizer.

The burner chamber portion of the incineration chamber begins with acylindrical section 61 concentrically surrounding the base end of theinjector. Following the cylindrical section is a coaxially alignedtruncated concical section 62 which terminates with annular step orledge 64 extending outwardly from the large end of the cone to the wallof the incineration chamber. The cone has an included angle of less thanand a length approximately equal to the radius of its large or upperend. The width of the ledge must be sufficient to prevent prematureattachment of the flames or hot reaction products to the wall of therefractory chamber. Preferably the ledge width is greater than theradius of the small end of the cone.

This system promotes rapid and substantially complete combustion of theoily waste fraction at a high temperature before the tempering effect ofwatery waste fraction influences the reaction. The efficiency of thissystem, wherein the waste fractions are admitted separately, over one inwhich the waste fractions are admitted as a mixture, is graphicallyshown in FIG. 3. The theoretical temperature curve in this figure is notattainable as a practical matter because a liquid waste containing theusual amounts of water, even though homogeneously mixed with thecombustible components, requires extra fuel in order to maintain astable flame.

While the principles of this invention are described with reference to apreferred embodiment illustrated in the drawings, it is to be understoodthat the description is made by way of example and that the scope of theinvention is to be limited only as defined in the appended claims.

What is claimed is:

1. A burner for burning pumpable non-homogeneous liquid having fractionswith different combustion characteristics, the combination comprising:an annular atomizing means; a second atomizing means coaxially mountedinside said annular atomizing means; means for separating the liquidinto two fractions, one of said fractions having a higher fuel valuethan the other of said fractions; meansfor supplying said higher fuelvalue fraction to said annular atomizer; and means for supplying theother of said fractions to said second atomizer.

2. A burner according to claim 1 wherein wall means defining an annularconduit is disposed about said second atomizing means, said annularatomizer includes an annular head adjacent the outlet end of saidannular conduit, said head being spaced laterally from the sides of saidconduit to form passages therebetween, an annularutlet groove located insaid head, an annular disc spaced above said head and extending from theinside wall of said conduit to adjacent its outside wall, means fordirecting a first high velocity gas stream across the open face of saidgroove, annular lip means extending from said groove in the direction ofsaid stream, means for directing a second high velocity gas streamacross the outer edge of said lip means at an abrupt angle with respectto said first gas stream.

3. A burner according to claim 2 including a means for varying therelative momentum of gas streams emitting from said atomizing meanswhereby the resultant direction of the streams is changed.

4. A burner according to claim 1 further including an annular conduitfor supplying a high momentum annular gas stream between said twoatomizing means.

' 1 n 14' x a w 3 1 v .4

(3.5L ll v. 11., (1.53 all; a; lililli in.) N

Patent No. I 3, 768, 961 Dated October 30, 1973 Inventor(s) Klaus H.Hernsath and Dale E. Wright It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrectedas shown below:

Column 1, line 30, delete "if" and substitute thereforit Column 3, lines48 -49, delete "The oily" and substitute therefor v side Line 58, delete"Theily" and substitute therefor The oily Column 4, line 34, change"concical" to conical Column 5, line 13, change "nularutlet" to nularoutlet Signed and sealed this 9th day of April 19%..

(SEAL) Atte st:

c MARSHALL DANN' Commissioner of Patents EDWARD MPLETGHERJR. AttestingOfficer

1. A burner for burning pumpable non-homogeneous liquid having fractionswith different combustion characteristics, the combination comprising:an annular atomizing means; a second atomizing means coaxially mountedinside said annular atomizing means; means for separating the liquidinto two fractions, one of said fractions having a higher fuel valuethan the other of said fractions; means for supplying said higher fuelvalue fraction to said annular atomizer; and means for supplying theother of said fractions to said second atomizer.
 2. A burner accordingto claim 1 wherein wall means defining an annular conduit is disposedabout said second atomizing Means, said annular atomizer includes anannular head adjacent the outlet end of said annular conduit, said headbeing spaced laterally from the sides of said conduit to form passagestherebetween, an annular outlet groove located in said head, an annulardisc spaced above said head and extending from the inside wall of saidconduit to adjacent its outside wall, means for directing a first highvelocity gas stream across the open face of said groove, annular lipmeans extending from said groove in the direction of said stream, meansfor directing a second high velocity gas stream across the outer edge ofsaid lip means at an abrupt angle with respect to said first gas stream.3. A burner according to claim 2 including a means for varying therelative momentum of gas streams emitting from said atomizing meanswhereby the resultant direction of the streams is changed. annularoutlet
 4. A burner according to claim 1 further including an annularconduit for supplying a high momentum annular gas stream between saidtwo atomizing means.